Ice rifter

ABSTRACT

An ice breaking apparatus including a floating platform, having buoyancy control means such as ballast tanks, valves and a source of water connected thereto for controlling the buoyancy of the platform and hydraulically extensible legs having feet adapted to rest upon the bottom for applying an upward force to the platform. The platform also includes apparatus for performing or weakening the ice such as a plurality of explosive charges to provide perforations and/or cracking along at least one edge of the platform as well as a system for raising the severed portions of ice from the water and sliding them onto the remaining ice.

United States Patent [191 [111 3,807,180 Worthing Apr. 30, 1974 ICERIFTER Primary ExaminerJacob Shapiro [76] Inventor: Robert w. Worthing,2301 N. w. Ammey Darby 16th Tern, Oklahoma City, Okla. s an 22 Filed:May 29, 1973 ABSTRACT Appl. No.: 364,639

An ice breaking apparatus including a floating platform, having buoyancycontrol means such as ballast tanks, valves and a source of waterconnected thereto for controlling the buoyancy of the platform andhydraulically extensible legs having feet adapted to rest upon thebottom for applying an upward force to the platform. The platform alsoincludes apparatus for performing or weakening the ice such as aplurality of explosive charges to provide perforations and/or crackingalong at least one edge of the platform as well as a system for raisingthe severed portions of ice from the waterand sliding them onto theremaining 14 Claims, 5 Drawing Figures slsomeo PAI'ENTEDAPR 30 m4 SHEET1 BF 2 & m mm m o PATENTEDAPR 30 I974 3.80711 86 sum 2 or 2 3&1

INVENTOR F; 055/? r h a rr/w/ys- ATTORNEYS 1c 1 RIFTER BACKGROUND OF THEINVENTION 1. Field of the Invention This invention pertains to icebreakers or rifters and, more particularly, to that class of ice rifterswhich comprises a submersible vessel having means for varying thebuoyancy thereof.

I 2. Descriptionof the Prior Art Mostknown ice breakers or 'riftersoperate by applying force to the top ofa sheet of ice. The vessels whichapply such forces must necessarily be very heavily armored and powerfuland thus very expensive because both a crushing force and a forceovercoming the buoyancy of the ice must be applied to break ice fromabove. I If force is applied from beneath the ice it need not be sogreat since it need not offset the buoyancy of the ice. Thus, the priorart has proposed three types of submersible vessels which 'are submergedto a level beneath the ice, inserted thereunder and then forced upagainst the ice to break it.

In the hydraulic type, the buoyancy of the submersible ice breakingvessel is varied by varying the contents of the ballast tanksincorporated into the body of the vessel. In the pneumatic type,buoyancy is varied by inflation of an expansible body forming part ofthe bottom of the submersible vessel. In the jet type, buoyancy isvaried by means of a fluid jet which is discharged through a downwardlydirected exhaust nozzle at the bottom of the vessel. In all of theseembodiments the pointof contact between the vessel and the ice is a typeof blade.

One problem with all of the above arrangements is that they only workwell in breaking relatively thin ice. As the ice becomes thicker, theamount of upward force needed to crack it also increases and thus, thesize of the buoyancy varying stream must also sharply increase. A secondproblem with existing arrangements is that they do not dispose of thebroken portions of the ice and thus these broken portions may float inthe cleared area to further hinder navigation.

SUMMARY OF THE INVENTION In order to overcomethe above stateddisadvantages the applicants have invented a submersible ice breakerwhich includes a separate means for applying an upward force to the iceabove the ice breaker besides the buoyancy of the ice breaker and, inaddition, includes a means for weakening the ice above the ice breaker.

More specifically, the applicants invention comprises a platformsupported by a variable buoyant means such as ballast tanks and havingat least one extensible member depending therefrom. The platform may besubmerged beneath the surface of the body of water having an icy surfaceby varying the buoyancy of the ballast tanks. Then the extensible membermay be extended'by a hydraulic actuator which forces the extensiblemember against the bottom and thus forces the platform upwards againstthe ice. Furthermore, a plurality of piercing or perforating means maybe affixed along at least one edge of the platform and directed towardsthe ice so as to weaken or perforate the ice when they are activated.Such means may comprise for example, lasers or may be a'series ofexplosive charges. Finally, a pair of hydraulic pistons disposed onopposite sides of a centerline of the platform and pivotally connectedthereto at their free ends (their fixed ends being connected totheballast tanks or the like) may be equally energized to lift the iceabove the level of adjacent ice and then one of the pistons may beenergized more than the other to tilt the'platform so that the ice mayslide onto the adjacent remaining ice.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiments of theinvention will now be discussed with reference to the following drawingsin which:

FIG. lis a partially schematic side view of an ice rifter according toafirst embodiment of the invention with its legs in a partially retractedposition.

FIG. 2 is a partially schematic side view of the ice rifter shown inFIG. 1 'with its legs in an extended position.

FIG. 3 is a detail of the embodiment of FIG. 1.

FIG. 4 is an end view'of the ice rifter shown in FIG. 2 wherein theplatform is shownin a tilted position.

FIG. 5 is a detailed 'view similar to FIG. 3 but showing anotherembodiment.

Similar elements are designated by similar reference numerals throughoutthe drawings.

DETAILED DESCRIPTION 0F THE PREFERRED EMBODIMENTS In FIG. 1 the icerifter or breaker is generally designated' by the numeral 10. The rifterincludes a platform 12 which may be a solid sheet of a strong materialbut which is preferably of a grid-like construction. The shape anddimensions of platform 12 are fixed by the area of ice which is desiredto be removed at a given time and the'top of the platform is smoothenough that ice will slide thereon if the platform is tilted. In theembodiments the platform is shown with a rectangular perimeter. Eachedge of the platform 12 has affixed to its perimeter a plurality ofperforating units which, in FIG. 3, are shown as shaped charge bearingunits 30 which are connected by electrical cables, to the supportvessel. The shaped charge units 30 are so shaped and positioned thatwhen they are ignited by electrical current from the cables 32 thecharges '33 are driven into and probably through the ice at intervalsof, for example, 4 to the foot. The units 30 are not novel per se, butrather are of the type conventionally used to perforate the steelcasings of oil wells and the oil bearing rock beyond to a distance ofover five inches. Thus, the charges 33 easily penetrate even greatthicknesses of ice and cause perforating holes therein adjacent theedges of platform 12. As shown in FIG. 5 the perforating units may alsocomprise electrically controlled lasers 35'which are aimed upwards atthe ice so that their beams penetrate the ice when the lasers areenergized.

As is best seen in FIG. 4, the platform 12 is attached to a framework14" which also supports a plurality of ballast tanks 16. The platform 12is linked to framework 1 4 at opposite ends by links 18a and 18b whichare pivotally connected at opposite ends to the framework and platform.As can be seen in the broken portion, a pin adjacent the top of eachlink such as link 18b is slidably received in a slot in the edge ofplatform 12.

The ballast tanks 16 are'connectedby-hose 17 to'a conventional supportvessel (not shown) which, conventionally, contains a pump forintroducing water. into and withdrawing it from the tanks 16 so that thebuoyancy of the platform 12 may be varied.

Depending from framework 14 near the four corners thereof are fourextensible tacking means in the form of leg structures 20a, 20b, 20c and20d of identical construction. These leg structures are pivotally andslid ably connected at' their upper ends to framework 14 and at. theirlower ends to feet 22a, 22b, 22c and 22d, respectively. Each legstructurecomprises a plurality of links interconnected in a conventionalmanner so that the legs have a partially retracted position, asshown inFIG. 1, a completely extended position, as shown in FIG. 4, and a fullyretracted position. The topmost in- I terconnecting links 24a, 24b, 24cand 24d, respectively,

Thus when the actuators 27a through 27d are ener-' gized they applyadownward force to the links 24a through 24b whereby the legstructures20a through 20d are extended.

The upper side of framework 14 supports the cylinder ends 34a and 34b ofthe hydraulic actuators 36a and 36b, respectively, while the pistonsthereof 38a and 38b, respectively, are pivotally connected to platform12. The hydraulic actuators 36a and 36b, as well as the hydraulicactuators 2711 through 27d may be energized from a source of pressurizedliquid carried by the support vessel. It is desirable, however, that theactuators 36a and 36b each have an individual control valve on itsrespective supply line while the actuators 27a through 27d shouldsimultaneously energized through a common control valve.

The operation of the ice rifter described above is as follows:

When the platform 12 has been towed to the area of use by the supportvessel, the buoyancy is adjusted by pumping water into ballast tanks 16until the platform 12 is beneath the surface of the body of water. Thesupport vessel then pushes the platform under'the ice and the ballastpumps withdraw some water. from tanks 16 to engage platform 12 with thebottom-of the ice.

Next, the charges 33-are ignited by electrical current from the supportvessel or, alternatively the lasers 35 are similarly energized to causeperforations around the edge of platform 12. If the ice is thin enoughthese perforations may so weaken it that the portion immediately abovethe platform is lifted freefrom the surface of the water. I I

If the ice above the platform does not separate from the remainder evenafter the ballast tanks have been pumped dry for maximum buoyancy, thenthe legs 24a through 24d are extended by actuators 27a through 27d,respectively, until they engage the bottom under the platform andjacking the latter upwardly to exert sufficient upward pressure on theiceabove the platform to sever it from the remainder of the ice.

Once the portion of ice above platform 12 has been severed from theremainder of the ice, the buoyancy of the ballast tanks 16 causes thesevered portion to be lifted above the remainder to the position shownin dotted lines in FIG. 4. The severed portion may then be lifted evenfurther by energizing the hydraulic actuators 36a and 36b. Then one ofthe actuators may be stopped while the other is continued in actuationwhich causes the severed ice to slide onto the remaining ice rather thanfloating in the cleared area. Of course, the operational steps justoutlined may be repeated as often as necessary to clear the desired areaof ice.

While the above description fully covers the preferred embodiments ofthe applicants invention, many changes may be made to these embodimentswithin the scope of the invention. Thus, for example, the means forvarying the buoyancy of platform 12 may be a fluid jet or an expansiblebody rather than ballast tanks. In addition, it may be found that thecharges are not necessary at each edge of platform 12 since at'least oneedge of the platform always faces clear water. Furthermore, thehydraulic actuators used in the preferred embodiments may be replaced bypneumatic or other conventional types of actuators. Finally, the shapedcharges 32 may be replaced by charges with bulletsor other projectiletips.

I claim:

'1. A method for removing'ice from the surface of a body of watercomprising the steps of:

v a. submerging a platform beneath the surface of said body of water,v

b. inserting said platform below at least a portion of the ice to beremoved,

c. weakening the ice along at least one edge of said platform bydischarging a plurality of explosive charges along at least one edge ofsaid platform in the direction of said ice,

d. lowering-at least one extensible member from said platform to engagethe bottom under said body of .water to, and w e. continuing to extendsaid extensible member to thus apply upward pressure to saidice untilsaid portion of ice is severed from the remainder of said ice.

.2. A method for removing ice from the surface of a body'of watercomprising the steps of:

a. submerging a platform beneath the surface of said body of water,

b. inserting said platform below at least a portion of the ice to beremoved, and I i c. weakening the ice along at least one edge of saidplatform by activating a pluralityof lasers which direct their beamsinto the ice, v

d. lowering at least one extensible member from said platform to engagethe bottom under said body of water to, and

e. continuing to extend said extensible member to thus applyupwardpressure to said ice until said portion of ice is severed from theremainder of said ice.

3. Apparatus for removing ice from the surface of a body of watercomprising-a platform, means for varying the buoyancy of said platformso that said platform can be submerged beneath the surface of said bodyof water, at least one extensible member connected at the first endtosaid platform and having an extended length greater than the depth ofsaid body of water, means for causing said extensible member to extendso that the second end of said member engages the bottom under said bodyof water and then continues to extend thus applying an upward force tosaid platform which severs a portion of said ice from the remainder, andmeans attached to said platform for weakening the ice along at least oneedge of said platform prior to severing of said portion of ice, saidmeans including a plurality of explo sive charges which are affixed tosaid platform so that the charges, when ignited, explode toward saidice, and means for igniting 'said chargesf i 4. Apparatus for removingice from the surface of a body of water comprising a platform, means forvarying the buoyancy of said platform so that said platform can besubmerged beneath the surface of said body of water, at least oneextensible member connected at the first end to said platform and havingan extended length greater than the depth of said body ofwater, meansfor causing said extensible member to extend .so that the second end ofsaid member engages the bottom under said body of water and thencontinues to extend thus applying an upward force to said platform whichsevers a portion of said ice from the remainder, and means attached tosaid platform for weakening the ice along at least one edge of saidplatform prior to severing of said portion of ice, said means includinga plurality of lasers affixed to said platform so that the laser beamspenetrate the ice when the lasers are energized.

5. Apparatus for removing ice from the surface of a body of watercomprising aplatform, means for varying the buoyancy of said platform sothat said platform can be submerged beneath the surface of said body ofwater, at least one extensible member connected at the I first end tosaid platform and having an extended length 6. The apparatus of claim 5wherein said tilting means comprises at least two hydraulically actuatedpistons which are disposed on opposite sides of a centerline of saidplatform, the free ends of said piston being pivotally connected to saidplatform while the fixed ends of the cylinders within which said pistonsare fixedly connected to said means for varying the buoyancy of saidplatform and means are provided for controlling the amount of extensionof said pistons so that one piston may be extended further than theothers to tilt said ice.

7. A method of removing ice from the surface of a body of watercomprising: submerging a generally horizontal platform beneath thesurface of the body of water, moving the platform horizontally to aposition below a portion of the ice to be removed, fracturing a portionof the ice above the platform, raising the platform to a position inwhich its upper surface is above the upper surface of the remainder ofthe ice, and tilting the platform to allow the fractured ice to slideonto the remainder of the ice.

8. A method as in claim 7 wherein the step of raising the platformincludes reducing the buoyancy of the platform. i Y i 9. A method as inclaim 7 wherein the step of raising the platform includes jacking theplatform from the submerged bottom of the body of water.

10. A method of removing ice from the surface of a body of watercomprising: submerging a platformbeneath the surface of a body of water,moving the platform horizontally to a position below a portion of theice to be removed, and jacking the platform against the submerged bottomof the body of water thereby raising the platform against the lowersurface of the ice.

11. Apparatus for removing ice from the surface of a body of watercomprising: a platform; means for adjusting the buoyancy of the platformso that it can float on the surface of the body of water or be submergedbeneath the surface of the body of water; and poweroperatedice-fracturing means carried by ,said platform for projectingice-fracturing forces upwardly from said platform and against the lowersurface of a layer of ice when said platform is submerged below thelayer of ice.

12. Apparatus as in claim 11 including means for tilting said platformrelative to the remainder of the apparatus to thereby permit fracturedice lying on top of said platform to slide off.

13. Apparatus as in claim 11 including extensible jack means rigidlyconnected to said platform for engaging a submerged bottom to therebyimpart an upward force on said platform.

14. Apparatus for removing ice from a body of water comprisingi aplatform; power-operated ice-fracturing means carried by said platformfor projecting icefracturing forces upwardly with respect to saidplatform and against the lower surface of a layer of ice when saidplatform is submerged below the layer ofice; and extensible jack meansrigidly connected to said platform for engaging a submerged bottom tothereby impart an upward force-on said platform. 7

1. A method for removing ice from the surface of a body of watercomprising the steps of: a. submerging a platform beneath the surface ofsaid body of water, b. inserting said platform below at least a portionof the ice to be removed, c. weakening the ice along at least one edgeof said platform by discharging a plurality of explosive charges alongat least one edge of said platform in the direction of said ice, d.lowering at least one extensible member from said platform to engage thebottom under said body of water to, and e. continuing to extend saidextensible member to thus apply upward pressure to said ice until saidportion of ice is severed from the remainder of said ice.
 2. A methodfor removing ice from the surface of a body of water comprising thesteps of: a. submerging a platform beneath the surface of said body ofwater, b. inserting said platform below at least a portion of the ice tobe removed, and c. weakening the ice along at least one edge of saidplatform by activating a plurality of lasers which direct their beamsinto the ice, d. lowering at least one extensible member from saidplatform to engage the bottom under said body of water to, and e.continuing to extend said extensible member to thus apply upwardpressure to said ice until said portion of ice is severed from theremainder of said ice.
 3. Apparatus for removing ice from the surface ofa body of water comprising a platform, means for varying the buoyancy ofsaid platform so that said platform can be submerged beneath the surfaceof said body of water, at least one extensible member connected at thefirst end to said platform and having an extended length greater thanthe depth of said body of water, means for causing said extensiblemember to extend so that the second end of said member engages thebottom under said body of water and then continues to extend thusapplying an upward force to said platform which severs a portion of saidice from the remainder, and means attached to said platform forweakening the ice along at least one edge of said platform prior tosevering of said portion of ice, said means including a plurality ofexplosive charges which are affixed to said platform so that thecharges, when ignited, explode toward said ice, and means for ignitingsaid charges.
 4. Apparatus for removing ice from the surface of a bodyof water comprising a platform, means for varying the buoyancy of saidplatform so that said platform can be submerged beneath the surface ofsaid body of water, at least one extensible member connected at thefirst end to said platform and having an extended length greater thanthe depth of said body of water, means for causing said extensiblemember to extend so that the second end of said member engages thebottom under said body of water and then continues to extend thusapplying an upward force to said platform which severs a portion of saidice from the remainder, and means attached to said platform forweakening the ice along at least one edge of said platform prior tosevering of said portion of ice, said means including a plurality oflasers affixed to said platform so that the laser beams penetrate theice when the lasers are energized.
 5. Apparatus for removing ice fromthe surface of a body of water comprising a platform, means for varyingthe buoyancy of said platform so that said platform can be submergedbeneath the surface of said body of water, at least one extensiblemember connected at the first end to said platform and having anextended length greater than the depth of sAid body of water, means forcausing said extensible member to extend so that the second end of saidmember engages the bottom under said body of water and then continues toextend thus applying an upward force to said platform which severs aportion of said ice from the remainder, and means attached to the top ofsaid platform for tilting the severed portion of ice so that it slidesonto the remaining ice.
 6. The apparatus of claim 5 wherein said tiltingmeans comprises at least two hydraulically actuated pistons which aredisposed on opposite sides of a centerline of said platform, the freeends of said piston being pivotally connected to said platform while thefixed ends of the cylinders within which said pistons are fixedlyconnected to said means for varying the buoyancy of said platform andmeans are provided for controlling the amount of extension of saidpistons so that one piston may be extended further than the others totilt said ice.
 7. A method of removing ice from the surface of a body ofwater comprising: submerging a generally horizontal platform beneath thesurface of the body of water, moving the platform horizontally to aposition below a portion of the ice to be removed, fracturing a portionof the ice above the platform, raising the platform to a position inwhich its upper surface is above the upper surface of the remainder ofthe ice, and tilting the platform to allow the fractured ice to slideonto the remainder of the ice.
 8. A method as in claim 7 wherein thestep of raising the platform includes reducing the buoyancy of theplatform.
 9. A method as in claim 7 wherein the step of raising theplatform includes jacking the platform from the submerged bottom of thebody of water.
 10. A method of removing ice from the surface of a bodyof water comprising: submerging a platform beneath the surface of a bodyof water, moving the platform horizontally to a position below a portionof the ice to be removed, and jacking the platform against the submergedbottom of the body of water thereby raising the platform against thelower surface of the ice.
 11. Apparatus for removing ice from thesurface of a body of water comprising: a platform; means for adjustingthe buoyancy of the platform so that it can float on the surface of thebody of water or be submerged beneath the surface of the body of water;and power-operated ice-fracturing means carried by said platform forprojecting ice-fracturing forces upwardly from said platform and againstthe lower surface of a layer of ice when said platform is submergedbelow the layer of ice.
 12. Apparatus as in claim 11 including means fortilting said platform relative to the remainder of the apparatus tothereby permit fractured ice lying on top of said platform to slide off.13. Apparatus as in claim 11 including extensible jack means rigidlyconnected to said platform for engaging a submerged bottom to therebyimpart an upward force on said platform.
 14. Apparatus for removing icefrom a body of water comprising: a platform; power-operatedice-fracturing means carried by said platform for projectingice-fracturing forces upwardly with respect to said platform and againstthe lower surface of a layer of ice when said platform is submergedbelow the layer of ice; and extensible jack means rigidly connected tosaid platform for engaging a submerged bottom to thereby impart anupward force on said platform.